This invention relates to a combined transmission system that transmits an oscillating input into a single direction output.
The prior art transmissions have not successfully transmitted high torque levels. One common type of transmission device is a one-way clutch. In these known systems: such as in U.S. Pat. No. 5,333,517 by Rodney Bryson, Aug. 02, 1994, rollers or other drive members are engaged within notches or openings in a driven member. The rollers engage and move the driven member when rotation is transmitted in a first direction, but will slip when rotation is transmitted in a second direction. The invention disclosed in U.S. Pat. No. 5,333,517 has a ratio between the worm and worm gear of 5, however, the number of threads on the worm is more than one, and the worm does not have a self locking feature. These types of clutches have enjoyed wide usage, but have been unable to transmit high torque loads. One proposal suggests using a pair of such clutches with an oscillating input to perform as a part of a vehicle transmission. Due to the low torque load, this system would be impractical. A main disadvantage of these types of clutches is a discrete characteristic of changing of contact. It leads to mechanical shocks during every new contact between driving and driven elements. Drive systems for providing speed in a single rotational direction from a reversible input are also well known (U.S. Pat. No. 5,333,517 by Rodney Bryson, Aug. 02, 1994). But this system has a gear train with some backlashes and it is not able to provide a small amplitude of vibration. Besides, the input and output shafts are perpendicular to each other, and therefore, this drive system cannot be used in many applications.
In one system disclosed in a Soviet inventor certificate number 1,495,110 (1989) granted to the inventor of this invention, a self-locking transmission is utilized to transmit rotation. In the disclosed system, a worm and a worm gear combination are utilized to transmit rotation. The rotation is transmitted utilizing the engaged teeth and thread of the gears such that there is not relative movement between the two gear members during this rotation. With such a system, many valuable benefits result. In particular, one is able to accurately and efficiently transmit rotation through the self-locking transmission. A main advantage of these types of clutches is continuous contact between the driving and driven elements.
In addition, the standard power supply utilized with such systems has difficulty allowing any of the structure to freely turn about 360 degrees. Instead, electrical supply lines have typically limited the operative members to a restricted range of rotation. This is, of course, undesirable.
The term "self-locking" as is utilized in this application to describe the inventive worm and worm gear combination, requires that the teeth of the worm gear when in contact with the thread of the worm, are incapable of rotating the worm about its axis. The teeth do not slip on the thread causing the thread to rotate about its own axis. By carefully selecting the material of the respective teeth and threads, and the respective angles, a worker of ordinary skill in the art would be able to achieve this goal.
There are some deficiencies in the system disclosed in the prior inventor's certificate, however, and this invention and a parent patent application of the same inventor, Ser. No. 08/732,150, filed Oct. 16, 1996 entitled "Worm/Wormgear Transmission And Apparatus For Transmitting Rotating Utilizing An Oscillating Input" disclose improvements to the prior art system, and PCT International Application No. PCT/US96/02918.